Conventionally, Patent Document 1 (Japanese Patent No. 4214964 corresponding to US 2005/0062005A) discloses regarding an electromagnetic valve. As shown in FIG. 8, the electromagnetic valve includes a yoke 100, a stator 110, a cylindrical cup guide 120, and a magnetism transfer member 140. The yoke 100 is arranged radially outward of a coil (not shown) to form a magnetic circuit, and the stator 110 is magnetized by energization of the coil to attract a plunger (not shown). The cup guide 120 is fitted to an inner circumference of the stator 110 and holds an outer circumference of the plunger slidably. The magnetism transfer member 140 is arranged between a step 130 provided in the yoke 100 and the stator 110 in an axial direction of the electromagnetic valve, and is used for transfer of magnetism between the yoke 100 and the stator 110. An outer circumferential surface of the cup guide 120 and an inner circumferential surface of the stator 110 define an inner circumferential gap β in a radial direction, and an inner circumferential surface of the yoke 100 and an outer circumferential surface of the stator 110 define an outer circumferential gap α in the radial direction. The outer circumferential gap α is larger than the inner circumferential gap β in the radial direction of the electromagnetic valve.
In the configuration in which the outer circumference of the plunger is slidably held by the cylindrical cup guide 120, the cup guide 120 is required to prevent from deforming. Thus, the cup guide 120 cannot be press-fitted and attached to the inner circumference of the stator 110 when the cup guide 120 is inserted radially inward of the stator 110. In other words, it is necessary for the inner circumferential gap β to be provided between the inner circumferential surface of the stator 110 and the outer circumferential surface of the cup guide 120 in order to insert the cup guide 120 radially inward of the stator 110.
In the above-described arrangement, a misalignment of the stator 110 and the plunger becomes large by the inner circumferential gap β, so that side force acting on the plunger, which is attraction force acting in its radial direction, increases. As a result, sliding friction generated between the cup guide 120 and the plunger increases when the plunger moves. Therefore, smooth moving of the plunger is limited, and abrasion between a sliding surface of the cup guide 120 and a sliding surface of the plunger may be increased.